1. Field of the Invention
This invention relates to a stability additive for distillate fuels.
More particularly, the present invention relates to stabilization of distillate fuels, particularly those which have a high acid number initially or which develop a high acid number as a result of fuel degradation, with a diaminomethane of the formula: ##STR2## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4 may be independently a saturated or unsaturated hydrocarbon group, e.g., alkyl, aryl, aralkyl, alkaryl, cycloalkyl, alkenyl, aralkenyl, alkenylaryl, cycloalkenyl and the like or heterocyclyl groups and in which R.sub.1 and R.sub.2 and/or R.sub.3 and R.sub.4 may be joined together to form a five or six member heterocyclyl ring and R.sub.5 may be hydrogen or lower alkyl.
Accordingly, it is an object of the present invention to provide a distillate fuel which is stabilized with a diaminomethane.
A further object is to provide a method for stabilizing a distillate fuel with a diaminomethane.
Other objects and features of the invention will be in part apparent and in part pointed out hereinafter, the scope of the invention being indicated by the subjoined claims.
2. Prior Art
The condensation products of formaldehyde and a number of primary amines are known to be useful in distillate fuels to increase color stability and resistance to sedimentation. These products have taken the form of a trimeric formaldimine, in the case of normal primary amines, or a monomeric formaldimine, in the case of aliphatic primary amines having a tertiary carbon atom attached to the nitrogen atom thereof.
Secondary amines are also known to react with formaldehyde, in this instance, to form diaminomethanes which have been used as biocides or alkylating agents. Insofar as known, however, diaminomethanes as herein described have not been recognized as useful in stabilizing distillate fuels, in general, or in stabilizing distillate fuels having a high acid number, in particular.